Forced induction is a process in which an air compressor is used for delivering compressed air to the intake of an internal combustion engine. Forced induction increases engine power and efficiency by increasing the total compression ratio and thermal efficiency of the entire system. Forced induction compressors are typically either turbochargers or superchargers. A turbocharger is an air compressor driven by a turbine that is turned by exhaust gases from the engine, with the turbine wheel and compressor wheel being on a common shaft. A supercharger is an air compressor that is mechanically driven by the crank shaft of the engine, typically by a belt, gear or chain.
The compressor wheels used for forced induction of internal combustion engines typically have a back plate supporting a plurality of blades that extend radially from a central hub and axially from the back plate.
The blades of a typical compressor wheel used for forced air induction are shaped to draw air axially into the compressor housing, accelerate the air centrifugally, and discharge the air radially from the compressor at a higher pressure.